Synchronizing mechanism for secondary clocks



Aug; 4, 1931.

c. E. LARRABEE 1,817,490 SYNCHRONIZING MECHANISM FOR SECONDARY CLOCKS Filed April 3. 1929 Patented Aug. 4, 1931 UNITED STATES PATENT OFFICE CLINTON E. LARRAIBEE, BINGHAMTON, NEW YORK, ASSIGNOR TO INTERNATIONAL TIME. RECORDING COMPANY OF NEW YORK, OF ENDICOTT, NEW YORK,-A CORPORA- TION OF NEW YORK SYN CHRON IZING MECHANISM FOR SECONDARY CLOCKS Application filed April 3, 1929. Serial No. 352,231. I

B) onda'ry clock.

It deals particularly with a system in which the secondary clock may receive electrical impulses over either one of two lines and make use of them according to its chronological condition of agreement or disagreement with a master clock which sends out the electrical impulses and causes the secondary clock to be stepped ahead if it be slow or to stop altogether if it be fast for a period of time equal to the amountthat it is fast and then resume normal operation.

The present invention concerns the provision of a new and efiicient automatic switching mechanism for use in a synchronized clock system of the type indicated.

The improved switching mechanism of the present invention forms that part of the synchronizing control operated by the secondary clock itself for use in connection with such a system as shown in U. S. patent to Bryce 1,687,491. In this system two wires, which may be distinguished as the A wire and the B wire are connected to the impulse devices of a master clock. During the greater portion of each hour minute impulses are sent over both wires. At the beginning of a synchronizing period usually the last fifteen mi nutes of each hour, the B wire is automatically disconnected from the impulse devices and receives no minute impulses until the end of the synchronizingperiod when it is autotrated 1n the accompanvlngdrawings is operating magnet from one wire tothe other.

When the secondary clock registers the last .minute of the synchronizing period. that is, the fifty-ninth minute after the hour its switching mechanism automatically connects its operating magnet to the B wire. Some time later usually about fifteen minutes the operating magnet is switched back to the A wire. It will thus be understood thatany secondary clock which registers slow will remain on the A wire during the synchronizing period until it receives enough of the fast impulses during the last minute of the hour to bring its'registration to fifty-nine minutes after the hour when it is automatically shifted to the B wire. Any secondary 'clock which registers fast will shift to the B wire when it registers 59 minutes after the hour and as the B wire receives no impulses during the synchronizing period such clocks will not move until the end of the period. When the B wire receives itsfirst minute impulse on the even hour all secondary clocks step off in unison and register the even hour. This systern forms per se no part of the present invention and need not be described in detail but the switching operations just explained m'ounted upon a front plate 2 and a rear plate 3 connected with each other by cross rods 4. Upon the plate 1 is mounted an electromagnet consisting of two magnet cores 5 and their associated magnet coils 6. p The hands 8 and 14 of the clock are driven by the usual gearing fromthe ratchet wheel 7 which is actuated by magnets 6 as will be explained. The ratchet wheel 7 is actuated whenever the operating magnet receives an impulse and is fixed to a shaft 9 journalled in the plates 2 and 3. At the opposite sides of said shaft is fixed the minute hand 8. The usual well known gear train reduction is provided between the minute hand 8 and the hour hand 14 including the gear 13 fast to a sleeve upon shaft 9 which sleeve carries the hour hand 14.

The armature 23 of he electromagnet is a. rectangular block mounted between two disks 43 and the assembly is journalled in a swingable frame. The frame consists of a cross piece 21 joining two vertical arms 17 and 18 which extend on opposite sides of the electromagnet and are pivoted on studs 15. The holes in the arms to accommodate the studs are slightly enlarged to permit lost motion and the arms and the whole swingable frame is pulled down by springs 19 anchored to the arms 17 and 18 and to clips on the studs 15. This seats the disks 43 firmly on a horizontal supporting plate 28 but permits them to roll thereon.

A curved pin 27 is fixed to the mid section of the armature and extends through a hole in plate 28. A spring 24 holds the swingable frame to the right. with respect to Fig. 2, with the block armature 23 at an angle to the vertical and the end of pin 27 engaged in the hole in plate 28. {)n energization of the magnet armature 23 tends to move into the most intense part of the magnetic field and owing to its constraint by the disks 43 and pin 27 causes the disks 43 to roll on the plate 28 to the position shown in Fig. 2. This rolling of the disks, of course, causes the arms 17 and 18 to rock slightly in a counterclockwise direction about the studs .15. j

The rocking movement of the frame, as just described, operates a pawl to stop the ratchet wheel 7. A stud shaft 29 is supported on a suitable bracket on front plate 2 and a plate 30 is pivotally mounted thereon. This plate is slotted at 33 to receive a pin 34 on arm 17. In normal rest position when arm 17 is held to the right in Fig. 2 by spring 24, pin

34 depresses plate 30 and an extension 30a moves between the ratchet teeth of wheel 7 v and holds the parts'firmly in position. A plate 31 has a bifurcated end which straddles shaft 29 and a pin 32 fast to plate 30 and extending through a hole in plate 31 holds these plates together. The end of plate 31 is bent sideways extending through a slot in plate 80 and is formed with teeth to act as a pawl coacting with the ratchet teeth of wheel 7.

A spring 35 .on pin 32 resiliently presses the teeth in the bent end of plate 31 against'the ratchet teeth. j

Vhen magnet 6 is energized causing arm 17 to rock counterclockwise to the position showh in-Fig. 2, pin 34 coacting with the curved edge of slot 33 raises plates 30 and 31 moving extension30'a sidewise'iout -of' engagement'with the ratchet'teeth andcausing.v the pawl teeth in plate 32 to click over ratchet;

wheel 7 for the space of one tooth; When f the magnet is deenergized spring 24 returns magnetfi to the A wire. When thesecondary clock registers'lfifty-nine minutes after the arm 17 to normal position and platesBO 31 are lowered stepping ratchet wheel 7 the space of one tooth and again locking it through extension 30a. This mechanism is fully described and claimed in copending application Serial No. 313,662 filed October 20, 1928.

The synchronizing contact mechanism forming the subject matter of the present invention is carried by aplate 44 fastened to the clock frameat 45 and 46. An insulating plate 47 fixed to plate has a contact block 48 connected to one terminal of the electromagnet 6 and contact elements 49, and 51 of which 51 is connected to the other terminet of magnet 6. The contacts 49 and 50 are provided with spaced fingers 49 and 50 and a spring finger 51 of contact 51 piays between them so that it may contact with either. A stud 52 on plate 44 carries a rotatable sleeve 53 to which is fixed a rod 54. Pivoted on this rod is a frame 58 having end extensions 56 and 57. Extension 57 is bifurcated to receive an insulating section on contact finger 51 so that when the frame is rocked about rod 54 this finger will alternately engage fingers 49 and 50'. The end piece 56 has two cars 59 and 60 and a center extension 73.

Cams 71 and 72 mounted on shaft 9 and thus operated by the clockwork, control the rocking of the frame 58 and a spring 75 pulls I when this comes under ear 60 the downward pull of spring 75 on rod 54 causes theframe 58 to shift so that bifurcated end 57 shifts contact finger 51' out of engagement with finger 50' and into engagement with finger 49".Somewhat later a step 78 on cam 71 comes under ear 59 and the frame 58 rocks back so that contact finger 51' again engages contact 50. The periods during which the contact finger '51 is in engagement with fingers 49 and 50 maybe selected as desired but ordinarily they will be selected for the system as previously mentioned.

,The circuit connections for a system such as disclosed in the Bryce Patent 1,687,491 previously mentioned is illustrated in Fig. 4. The/A wire receives an impulse every minute and a series of fast impulses during the.

last: minute of each hour. The B wire receives minute impulses from the even hour' to'forty five minutes thereafter; The C wire rms a common return. Owing'to the configuration of the cams 71 and 72 the contacts from the spirit-of the invention.

hour contact 51 shifts into engagement with contact 49 thus connecting the magnet 6' to the wire and this connection persists until some time after the even hour whereupon the magnet 6 is shifted back to the A wire. The

synchronizing of the secondary clocks will be understood from the explanation of the system previously givens While there has been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing It is the intention therefore. to be limited only as indicated by the scope of the following claims: 1. In a secondary clock, a driving magnet controlled by an actuating circuit, a driving shaft carrying the hands of the clock on its one end and a pair of stepped cams on its opposite end, said shaft being actuated by said magnet, a pivotally mounted rod arranged parallelly to the plane of said cams,

a switching velement, pivotally supported by said rod and connecting said driving magnet with different lines of said actuating circuit,

said switching element having wing portions- 7 on opposite sides of the axis of said rod, each wing port-ion riding upon an associated stepped cam to pivot said switching element into different switching positions by the steps of said cams. a

2. In a secondary clock, an automatic switching mechanism including a pivotally supported shaft, a switching element rotatably supported by'said shaft and a switching of clock controlled cam elements coacting with said switching element to pivot said switching element about said shaft into different switching positions.

3. In a secondary clock, an automatic switching mechanism including a pivotally supported shaft, a switching element rotatab y a pair of clock controlled cam elements arranged parallelly to said shaft and enacting with the switching element supported by said shaft to pivot said element about said shaft into different switching positions.

supported by said shaft and a switchingblade controlled by said switching element,

na-l portions supported by said rod, one of said terminal portions having a bifurcation guiding said switching element and the opposite bent terminal portion having a finger passing between said cams and a wing portion on each side of'said finger, each wing portion riding on the Surface of an associated ca1n.,

5. A mechanism according to claim 4 wherein means are provided to 'engage said wing portions resiliently with said cams to effect tilting ofsaid bar upon dropping of a wing off a step of its associated cam.

6. In a secondary clock, an automatic switching mechanism including in combination, a pivotally mounted rod, a switching element tiltably supported by said rod, a plurality of stepped cams controlled by the clock mechanism the steps of said cams c0- acting with said switching element to tilt the same alternately in opposite directions upon subsequent coaction with steps of different cams.

7. In a secondary clock, an automatic switching mechanism including in combination. a pair of cams mounted on the driving shaft of said clock each cam having a step, said steps being displaced from each other for a predetermined amount, a pivotally mounted rod extending approximately tangentially to said cams, a switch element comprising a plate having rectangularly bent terminal portions each having a hole through which said rod passes to support said switch element in proximity of the ends of said rod,

one terminal portion having a bifurcation, an

insulating piece carrying a switch blade said insulating piece being guided by said bifurcation, and the'opposite terminal portionhaving two wings on opposite sides of said rod, A

signature. y CLINTQN E. LARRABEE.

[4. In a magnetically driven secondary clock.- a plurality of terminals of different feed lines, a terminal for a common back line, said terminal being connectedwith said magnet and a switching element under the control of said clock mechanism to selectively connect either one of said feed line terminals with said magnet, said means comprising a pair of stepped cams, a pivotally mounted rod extending parallelly to the plan of said cams, a bar having rectang'ularly bent termi- 

